Description

The SC16C554BIBS is a high performance UART (Universal Asynchronous Receiver Transmitter) electronic component. It is designed to drive an external power switch to generate programmable negative voltages, making it particularly suitable for LCD bias contrast applications. With a maximum efficiency of 90%, it can achieve high performance while using low cost PNP bipolar transistor drivers. The input operation range of 4V to 24V allows it to be powered directly by the battery pack in most battery-operated applications, increasing efficiency. The output voltage can be scaled to -40V using two external resistors. It employs a pulse frequency modulation scheme to maintain high efficiency conversion under wide input voltage ranges. The SC16C554BIBS has a quiescent current of about 100µA, which can be reduced to 8µA in shutdown mode. Its switching frequency ranges from 100kHz to 320kHz, allowing the use of small size switching components. This makes it ideal for battery-powered portable equipment such as notebook and palmtop computers.

Specifications and features

- 4V to 24V input voltage operation

- Adjustable output voltage up to -40V

- Low quiescent current at 100µA

- Pulse frequency modulation maintains high efficiency (max 90%)

- 100kHz to 320kHz switching frequency

- Power-Saving shutdown mode (8µA typical)

- High efficiency with low cost external PNP bipolar transistor

Application Scenarios

- Negative LCD contrast bias for:

1. Notebook & palmtop computers

2. Pen-based data systems

3. Portable data collection terminals

4. Personal digital assistants

- Negative voltage supplies

Comparison

- High performance with a maximum efficiency of 90%

- Suitable for LCD bias contrast applications

- Wide input voltage range of 4V to 24V

- Adjustable output voltage up to -40V

- Low quiescent current at 100µA

- Pulse frequency modulation for high efficiency conversion

- Small size switching components can be used

- Requires an external power switch for generating negative voltages